Modern vehicles are frequently equipped with multi-speed, dual-clutch transmissions (DCT) as part of the subject vehicle's powertrain. Such DCTs are favored for their increased mechanical efficiency in comparison with typical, torque-converter equipped automatic transmissions. Additionally, DCTs are often preferred over typical automated manual transmissions for the capability of DCTs to provide higher quality gear shifts.
A typical DCT employs two friction clutches for shifting among its forward ratios, and accomplishes such shifts by alternating engagement between one and the other of the two friction clutches. Such a multi-speed, dual-clutch transmission may be utilized in a hybrid vehicle, i.e., a vehicle employing two or more distinct power sources, such as an engine and an electric motor, for transmitting propulsion energy to the subject vehicle's driven wheels.
During operation of a vehicle equipped with a DCT, significant amounts of heat or thermal loads may be generated within the DCT clutches due to clutch slip used to launch the vehicle and during gear shifts. When such loads exceed specific thresholds, performance and durability of the DCT clutches, as well as general performance of the DCT and the vehicle, may be adversely affected.